html,body {
  height: 100%;
}
.box {
  filter:progid:DXImageTransform.Microsoft.gradient(startColorstr='#6699FF', endColorstr='#6699FF'); /*  IE */
  background-image:linear-gradient(bottom, #6699FF 0%, #6699FF 100%);
  background-image:-o-linear-gradient(bottom, #6699FF 0%, #6699FF 100%);
  background-image:-moz-linear-gradient(bottom, #6699FF 0%, #6699FF 100%);
  background-image:-webkit-linear-gradient(bottom, #6699FF 0%, #6699FF 100%);
  background-image:-ms-linear-gradient(bottom, #6699FF 0%, #6699FF 100%);

  margin: 0 auto;
  position: relative;
  width: 100%;
  height: 100%;
}
.login-box {
  width: 100%;
  max-width:500px;
  height: 400px;
  position: absolute;
  top: 50%;

  margin-top: -200px;
  /*设置负值，为要定位子盒子的一半高度*/

}
@media screen and (min-width:500px){
  .login-box {
    left: 50%;
    /*设置负值，为要定位子盒子的一半宽度*/
    margin-left: -250px;
  }
}

.form {
  width: 100%;
  max-width:500px;
  height: 275px;
  margin: 25px auto 0px auto;
  padding-top: 25px;
}
.login-content {
  height: 300px;
  width: 100%;
  max-width:500px;
  background-color: rgba(255, 250, 2550, .6);
  float: left;
}


.input-group {
  margin: 0px 0px 30px 0px !important;
}
.form-control,
.input-group {
  height: 40px;
}

.form-group {
  margin-bottom: 0px !important;
}
.login-title {
  padding: 20px 10px;
  background-color: rgba(0, 0, 0, .6);
}
.login-title h1 {
  margin-top: 10px !important;
}
.login-title small {
  color: #fff;
}

.link p {
  line-height: 20px;
  margin-top: 30px;
}
.btn-sm {
  padding: 8px 24px !important;
  font-size: 16px !important;
}
